1. Field of the Invention
The present invention relates generally to radio frequency (RF) transceivers.
2. Background Art
In a wireless device, the power efficiency of a power amplifier (PA) can be increased by having the PA supply voltage signal track the instantaneous power being produced by the PA. This, however, requires the PA supply voltage to have at least as much bandwidth as the envelope of the desired transmit signal.
Commonly, the PA supply voltage is produced using a circuit path with a low-pass transfer function. As such, high frequency components of the envelope of the desired transmit signal are attenuated, and the envelope tracking performance may be degraded when the desired transmit signal envelope has greater bandwidth than the circuit path can support.
The present invention will be described with reference to the accompanying drawings. Generally, the drawing in which an element first appears is typically indicated by the leftmost digit(s) in the corresponding reference number.